Device for packaging piece goods on a base frame

ABSTRACT

IN APPARATUS FOR SHRINKING AN ENVELOPE OF SYNTHETIC MATERIAL ONTO A STACK OF PIECE GOODS OR A BASE FRAME, SUCH AS A PALLET, THERE IS PROVIDED A PERMEABLE AREA IN THE PLATFORM SUPPORTING THE BASE FRAME AND SUCTION MEANS SO THAT A CURRENT OF AIR FLOWS DOWNWARDS THROUGH THE PERMEABLE OVEN WHEREBY THE PORTION OF THE ENVELOPE PROTRUDING BELOW THE STACK OF PIECE GOODS IN THE BASE FRAME IS TURNED INWARDLY UNDER THE BASE FRAME, SO THAT MANUAL PREFASTENING IS OBVIATED.

Nov. 23, 1971 Go E 3,621,588

DEVICE FOR PACKAGING PIECE GOODS ON A BASE FRAME Filed Sept. 9. 1969 INVENTOR. 0/5 TH/EL /vz woe/(E.

BY )MMM) D y E United States Patent O DEVICE FOR PACKAGING PIECE GOODS ON A BASE FRAME Diethelm Grocke, Nuremberg, Germany, assignor to Nutro Hirsch 8: (10., Nuremberg, Germany Filed Sept. 9, 1969, $81. No. 856,370 Claims priority, application Germany, Oct. 10, 1968, G 68 01 652 Int. Cl. B651) 1/02 US. Cl. 34-225 4 Claims ABSTRACT OF THE DISCLOSURE In apparatus for shrinking an envelope of synthetic material onto a stack of piece goods or a base frame, such as a pallet, there is provided a permeable area in the platform supporting the base frame and suction means so that a current of air flows downwards through the permeable oven whereby the portion of the envelope protruding below the stack of piece goods in the base frame is turned inwardly under the base frame, so that manual prefastening is obviated.

BACKGROUND OF THE INVENTION The invention relates to an apparatus for packaging piece goods (pieces of merchandise) adapted to be stacked on a base frame, the apparatus being equipped with a heater for shrinking an envelope of synthetic material pulled over the piece goods stacked on the frame base and with a platform for the base frame.

In one known form of apparatus for packaging piece goods in a shrinkable envelope of synthetic material, shrinking of the envelope is effected under the influence of hot air. The hot air is led to the stack of piece goods covered by the envelope passes, during the shrinking process, along the envelope either upwards or downwards.

In order to attain optimal safety during shipment it is, however, necessary for the synthetic material envelope extending beyond the base frame to be shrunk under the base frame and to form a functional unit consisting of stacked goods and base frame. This under-shrinking has hitherto been obtained by prior manual fastening of the envelope ends under the frame base.

The present invention has as an object the provision of means for ensuring that the synthetic material envelope automatically shrinks under the base frame during the shrinking process, so as to make the above described manual operation unnecessary.

SUMMARY OF THE INVENTION According to the invention, this is achieved by constructing the platform so as to be air-permeable within an area the dimensions of which correspond to the dimensions of the base frame, and by providing a suction device which sucks air through this air-permeable portion of the platform, from above.

Preferably, the platform is air-permeable in its central region. By means of the suction device, air is sucked out of the stack of piece goods covered by the envelope and through the platform and base frame, so that a slight negative pressure develops inside the envelope. Because of this negative pressure, the envelope adheres closely to the piece goods stack, and the portion of the envelope depending loosely beyond the bottom edges of the base frame, which portion is within reach of the suction of the suction device, is in an advantageous manner and Without the operators assistance, folded in a direction to Wards the central region of the base frame. This folding is, in particular, also effected by air between the base frame and the platform being sucked out of the space surrounding the base frame.

The portion of the envelope folded under the base frame also shrinks under the influence of the heat so that a union of the piece goods and the base frame is establlshed in a simple manner by means of the undershrunk envelope of synthetic material.

To facilitate rapid and simple delivery of the frame base with the piece goods stacked thereon, the base frame is suitably adapted to be deposited on an air-permeable transport device which shifts the base frame in a horizontal direction. Air-permeability is necessary so that the suction device may suck the air out of the piece goods stack and from the space surrounding the base frame. The transport device thereby forms part of the platform, as is the case e.g. with a beltor chain-conveyor.

A conventional fan may serve as suction device, e.g. an axial or radial fan, the motor of which is disposed directly under the platform. The fan may be seated on the transport device but better still, on the solid ground beneath the transport device. In another embodiment a suction line may, however, serve as the suction device, the air being sucked from the piece goods stack through the suction line by a fan disposed at any convenient location.

Suitably, a piece goods packaging apparatus of the kind initially described has a hot air oven provided with air channels perforated toward the oven chamber in two opposed walls of the oven, an appropriately perforated ceiling, a thermometer above the ceiling, and two ventilators sucking air out of the oven chamber and leading it into the air channels. Such an arrangement may be advantageously be improved by the oven having a double floor, the upper layer of which is formed, at least in part, by the platform, and the space between the two layers serving to conduct the air sucked off by the suction device associated with the platform, with the upper layer being provided in its lateral regions adjacent the air channels with perforations toward the oven chamber. With such an arrangement, it is possible to conduct the air sucked through the platform to the air circulating through the oven chamber and the two air channels, thus achieving an enhanced efficiency of the installation.

It is advantageous to point the perforations of the upper filoor-layer at the bottom edges of the frame base carrying the piece goods and the perforations should preferably be in the form of nozzles. As a result, the part of the envelope depending beyond the bottom edges of the frame base and being drawn together by the suction effect of the sucked off air, will then adhere even more closely to the bottom of the frame base, under the influence of the supplementary blowing action.

Suitably, the perforations of the air channels to the oven chamber may be disposed near the floor and the hot air may be directed obliquely toward the lateral edge regions of the floor, adjacent the air channels. The hot air current sucked from the oven chamber by the two ventilators above the ceiling can consequently rise along the envelope of synthetic material. Thus, one achieves moreover, in an advantageous manner, that all the circulating air sweeps along the sides of the envelope.

In a further development of the apparatus of the invention, it is advisable to make the outlet direction of the perforations of the air channels and/or of the upper floor-layer adjustable, so that the desired effect of folding the envelope under the frame base can be obtained also for piece goods stacks on base frames of different dimensions.

The suction line of a hot air oven having a suction device in the form of a suction line may also be connected to the suction side of the ventilators associated with the air channels. An air sucking appliance proper, e.g. an

axial fan, will then not be required, so that, when constructing such an apparatus, one need not arrange for the suction appliance disposed in the space between the two floor-layers or, as the case may be, underneath the lower floor-layer, to be accessible for maintenance purposes.

In an apparatus of the kind initially mentioned, it is useful to provide a framework which is vertically displaceable on guide means and which has a heat emitting element connected to a heater. If all or some of the above mentioned features of the invention are realized in such an apparatus, it is advisable to make it possible for the air sucked off by the suction device associated with the platform to be conducted to the heater.

Two preferred embodiments of the invention are illustrated in the accompanying drawing, in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 each show a vertical section through one of the embodiments.

DETAILED DESCRIPTION OF THE DRAWINGS In FIG. 1, a cube-shaped stack 1 of piece goods having an associated rectangular base frame 2 is deposited on a transport means 4 disposed in the interior of a hot air oven 3. An envelope 5 of synthetic material is pulled over the piece goods stack 1, with the envelope loosely depending beyond a bottom 6 of the base frame 2. The base frame 2 may also be referred to as a pallet.

The transport means 4 rests on the upper side of an upper layer 7a of a double floor. The upper side of the upper layer 7a of the double floor thereby simultaneously represents platform 7. This transport means 4 can be imagined e.g. as a simple plank carriage or as a beltor chain-conveyor. In the central region of the upper layer 7a of the double floor, the blade of an axial fan driven by an electric motor is arranged to rotate substantially in the plane of the upper floor-layer 7a. The air sucked by this blade from the interior of the envelope 5, i.e. from the piece goods stack 1, causes the envelope 5 to adhere firmly to the upper surface and to the sides of the stack 1 and the air is led through an interspace 10 of the double floor to the opposed sides of oven chamber 11, to nozzle-like perforations 12 directed toward the center of the oven chamber 11.

The sucked off air introduced into the oven chamber 11 through the perforations 12 blows, because of the disposition of the perforations 12, toward the lower edges of the base frame 2, so that the envelope 5 which is being drawn towards the central area of the base frame 2 by the suction of the fan blade, applies itself even more closely to the bottom '6 of the base frame 2. The sucked off air introduced into the over chamber 11 from the interspace 10 of the double floor, through the perforations 12, mixes in the region of the lower longitudinal edges of the interior of the oven 3 with the hot air introduced into the oven space 11 through perforations 13. The perforations 13, which are provided only in the lower region of the interior side-walls of the hot air oven 3, are also constructed in the form of nozzles, similar to the perforations 12 of the upper layer of the floor. The hot air currents from the perforations 13 are directed inwardly toward the floor of the oven chamber 11 and they mix with the current of sucked off air. By a suitable disposition of the outlet angles of the perforations 12 and of the perforations 13, a hot air current can be produced in an advantageous manner, as shown by the arrows, which current, starting at the lower edge of the frame base 2, rises along the vertical surfaces of the piece goods stack 1 to the ceiling (not shown) of the oven space 11.

The hot air is led, in each case, to the perforation 13 through an air channel 14 at the upper end of which 4 a blower is provided which urges the hot air, conveyed through the perforated ceiling of the oven space 11 to a heat control (not shown) and into the air channels 14.

The portion of the envelope 5 which originally extended beyond the lower side 6 of the base frame 2 is applied to the lower side 6 during the shrinking process, in such a manner that after the shrinking process, the piece goods stack 1 can only be parted from the base frame 2 by the destruction of the envelope 5.

In the second embodiment illustrated in FIG. 2, a frame 16 is arranged to be displaceable along two vertical guide means 15. The frame 16 comprises a heat emitting element (not shown) for shrinking the envelope 5 of synthetic material pulled over the piece goods stack 1. The frame 16 is of annular shape, corresponding to the horizontal cross section of the piece goods stack 1 or of its base frame 2. The base frame 2 is supported by the platform 7 which latter, as indicated by the arrows, is air-permeable in its central region. Under the platform 7 there is again disposed an electric motor driven rotor of an axial fan 9.

The air sucked by the fan 9 out of the piece goods stack and from the space laterally surrounding the base frame is, in this embodiment, blown into the ambient atmosphere. As to shrinking of the synthetic envelope 5 and its contraction below the lower side of the frame base 2, the same remarks apply for this embodiment as were made regarding FIG. 1. This second embodiment differs from the first one as to the way it works, in that the shrinking of the envelope does not occur all over the envelope at the same time, but in bands encircling the piece goods stack 1, this band-like shrinking area descending as the frame 16 is lowered on the guides 15, until the frame 16 is finally lowered so far that it lies at the level of the platform 7.

In the second embodiment too, it is in principle possible to support the base frame 2 on transport means and to arrange the latter in the plane of the platform 7 or slightly higher than the latter.

I claim:

1. An oven for shrinking a plastic envelope over piece goods stacked on a base frame with a portion of the envelope extending below the base frame, comprising a platform which is air-permeable over an area adapted to receive the base frame, two walls facing each other on either side of the air-permeable area, said walls having nozzles directed obliquely downwardly toward the air-permeable area of the platform, conduit defining means leading from the interior of the oven to the nozzles, and suction means for drawing air downwardly through the air-permeable area of the platform and for driving air through the conduit defining means to the nozzles whereby the air is directed toward the extending portion of the envelope to move said portion under the base frame to provide a unit defined by the piece goods, envelope and base frame.

2. An oven for shrinking a plastic envelope over piece goods stacked on a base frame with a portion of the envelope extending below the base frame, comprising a double floor defined by an upper layer and a lower layer providing an interspace therebetween, said upper layer having an air-permeable area adapted to receive the base frame, two walls within the oven facing each other on either side of the air-permeable area, said walls having nozzles directed obliquely downwardly toward the airper-meable area of the upper layer, said upper layer being provided with nozzles directed toward the bottom of the base frame, and suction means for drawing air downwardly through the air-permeable area of the upper layer and for driving said air through the nozzles of the upper layer whereby the air leaving said nozzles is directed toward the extending portion of the envelope to move said portion under the base frame to provide a unit comprising the piece goods, envelope and base frame 5 and air being driven through the nozzles of the walls for mixing with the air leaving the nozzles of the upper layer.

3. The apparatus as claimed in claim 1 in which the suction means comprises a motor driven fan located directly below the platform.

4. The apparatus as claimed in claim 2 in which the suction means comprises a motor driven fan having its blade located in the air-permeable area of the upper layer for rotation substantially in the plane of the upper layer and the nozzles of said walls being located close to the upper layer of the double floor.

6 References Cited UNITED STATES PATENTS 4/1970 Myers 53-30 8/1970 Kaliwoda et al. 53---30 US. Cl. X.R. 

